i have one question..
in 2011 bitcoins per 50,000 to 500,000 we spent for nothing, just pranking and stuff...
if one person kept 50,000 bitcoins in his account from 2011 up till now,
would the bitcoins still be valid for transactions?
Of course, that would still be valid until now. As long as it is bitcoin and bitcoin is valid, those are greatly valid transcations with high price. Just remember to keep your private keys until now and surely, you could still use it.